93 zj 5.2 no spark...sometimes - Pirate4x4.Com : 4x4 and Off-Road Forum

4x4troy · 06-28-2011, 03:35 PM

Here is what is happening.

Jeep has very hard time starting, and currently will not start.

Vehicle - 93 Jeep Grand Cherokee Laredo 4x4 5.2

replaced coil
replaced auto shutdown relay
replaced battery
redid battery connection and verified all grounds to the engine
grounded out security system inside driver door

Here is what I was able to do until yesterday to get vehicle to start, once running it runs great, but
getting it started is getting worse and worse to accomplish.

1. Turn on Key
2. let sit for approx 30 seconds - security light comes on in dash (even after grounding out system)
3. let sit for approx 1-2 minutes - auto shutdown relay clicks rapidly for 3-5 seconds
4. check engine light comes on
5. able to start engine on first turn of key, catches immediately and runs great

Now - never get the rapid clicking in the auto shutdown relay, engine will not catch, cranks but will not
catch and start.
more...
i found some broke wires in the drivers door jam and hooked them back up.
now i get the rapid clicking again from the auto shutdown but it still wont start...and i can hear the fuel pump again.

Marty, SoCal · 07-02-2011, 07:05 AM

Probably has a bad crank position sensor. It is a very common failure. It's mounted near the top of the transmission below the passenger side head, it's removed with a 1/4" allen wrench. Kind of a pain to get to on a '93 due to the EGR tube being in the way. I used to use a small piece of 1/4 allen wrench glued into a 1/4" drive 1/4" flex socket with a 6" extension to access it without removing the EGR tube.

06-28-2011, 03:35 PM	#1 (permalink)
4x4troy Registered User Join Date: Apr 2010 Member # 159299 Posts: 55	93 zj 5.2 no spark...sometimes Here is what is happening. Jeep has very hard time starting, and currently will not start. Vehicle - 93 Jeep Grand Cherokee Laredo 4x4 5.2 replaced coil replaced auto shutdown relay replaced battery redid battery connection and verified all grounds to the engine grounded out security system inside driver door Here is what I was able to do until yesterday to get vehicle to start, once running it runs great, but getting it started is getting worse and worse to accomplish. 1. Turn on Key 2. let sit for approx 30 seconds - security light comes on in dash (even after grounding out system) 3. let sit for approx 1-2 minutes - auto shutdown relay clicks rapidly for 3-5 seconds 4. check engine light comes on 5. able to start engine on first turn of key, catches immediately and runs great Now - never get the rapid clicking in the auto shutdown relay, engine will not catch, cranks but will not catch and start. more... i found some broke wires in the drivers door jam and hooked them back up. now i get the rapid clicking again from the auto shutdown but it still wont start...and i can hear the fuel pump again. __________________ '94 Land Rover disco 1, 3.9 v8, my project '95 Nissan Pathfinder 4x4 xev6, 3.0 auto., daily driver

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07-02-2011, 07:05 AM	#2 (permalink)
Marty, SoCal Registered User Join Date: May 2011 Member # 191442 Location: SoCal Posts: 261	Probably has a bad crank position sensor. It is a very common failure. It's mounted near the top of the transmission below the passenger side head, it's removed with a 1/4" allen wrench. Kind of a pain to get to on a '93 due to the EGR tube being in the way. I used to use a small piece of 1/4 allen wrench glued into a 1/4" drive 1/4" flex socket with a 6" extension to access it without removing the EGR tube.